The kinetics and mechanisms of aromatic halogen substitution. Part XXVII. Substitution products in the chlorination of triphenylene

Chlorination of triphenylene by chlorine in acetic acid at 25° gives 1- and 2-chlorotriphenylene in the ratio 73 : 27. A small proportion of addition accompanies substitution. These results confirm the qualitative prediction derived from certain theoretical parameters that the 1 - is intrinsically more reactive than the 2-position, and suggest that, for molecular chlorine and reagents no more demanding sterically, there is little steric hindrance to attack at this type of position.